<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
<style>
    .box{
        width: 300px;
        height: 300px;
        padding: 30px;
        margin: 50px;
        border:5px solid darkorange ;
        background-color: blueviolet;

    }
    .yellow:hover{
               color: blue;
               
    }
    .green:hover{
               color: darkorange;
    }
    li:hover{
         background-color: pink;
     
    }
    .items{
        width: 1260px;
        height: 200px;
        background-color: orange;
        margin: 0 auto;
    }
    .blue
    {
          background-color: blue;
    }
    .item{
        width: 300px;
        height: 200px;
        background-color: red;
        display:inline-block
    }
    
</style>
</head>

<body>
    <!-- 00 -->
    <div class="box"></div>
    <!-- 01 -->
    <!-- <ul>
        <li><a href="http://www.baidu.com/" class="yellow">百度</a></li>
        <li><a href="http://www.baidu.com/" class="green">新浪</a></li>
    </ul> -->
    <!-- 02 -->
    <ul class="items">
        <li class="item"></li>
        <li class="item"></li>
        <li class="item blue"></li>
        <li class="item"></li>
    </ul>
</body>

</html>